Conventional fuel delivery systems in the automotive industry are mostly of the returnless type. As a consequence, these systems require an energy absorbing device to mitigate fuel pressure pulsations and/or audible noise generated in the fuel rail due to the normal sequential firing of injectors. This energy absorbing device, commonly known as a fuel pressure damper, is conventionally mounted on the fuel rail.
Most fuel pressure dampers used today are a mere modulate of pressure regulators, hence they do not fulfill the requirement of fuel rail volume change at all levels of engine operation, i.e., all rpms. Almost all conventional dampers have very little movement of the spring and the diaphragm system. Conventional fuel pressure dampers can be tuned to only a limited operating range. These dampers thus help to minimize the pressure pulsation problem in only one range, whereas the fuel system is left desiring at other operating ranges, which may be a nuisance of equal or lesser severity. The current alternative is to choose either a high frequency range or a low frequency range and tune the damper to the more damaging range. This drawback is getting increasingly magnified in today's trend of fuel systems moving towards a higher pressure and frequency range.
The limitations of conventional dampers arise from both the spring and the diaphragm. Conventional helical compression springs are effective and respond equally only to a small window of load. Another important limiter in current dampers is the diaphragm. Conventional diaphragms are flat and have very little displacement, thus limiting their contribution in making a significant volume change. These diaphragms are mainly dependent on the spring for a significant volume change and are also vulnerable to failure upon exposure to overload or higher magnitude pressure pulsations.
Thus, there is a need to provide a fuel pressure damper that is effective in the entire engine operating range of pressure and frequency.